The major active component of marijuana could enhance the ability of the virus that causes Kaposi’s sarcoma to infect cells and multiply, according to a team of researchers at Harvard Medical School. According to the researchers, low doses of Ä-9 tetrahydrocannabinol (THC), equivalent to that in the bloodstream of an average marijuana smoker, could be enough to facilitate infection of skin cells and could even coax these cells into malignancy.

While most people are not at risk from Kaposi’s sarcoma herpes virus (KSHV), researchers say those with lowered immune systems, such as AIDS patients or transplant recipients, are more susceptible to developing the sarcoma as a result of infection. Their findings, reported in the August 1 issue of Cancer Research, a journal of the American Association for Cancer Research, offer cautionary evidence that those with weakened immune systems should speak with their doctors before using marijuana medicinally or recreationally.

“These findings raise some serious questions about using marijuana, in any form, if you have a weakened immune system,” said lead study author Jerome E. Groopman, M.D., professor of medicine at Harvard Medical School. “While THC is best known as the main psychotropic part of marijuana, an analog of THC is the active ingredient of marinol, a drug frequently given to AIDS patients, among others, for increasing appetite and limiting chemotherapy-induced nausea and vomiting.”

While previous studies indicated that marijuana smoking was associated with Kaposi’s sarcoma, this is the first to demonstrate that THC itself can assist the virus in entering endothelial cells, which comprise skin and related tissue.

According to Dr. Groopman, the study illustrates the complicated role marijuana and other cannabinoids play in human health. Numerous types of cells display cannabinoid receptors on their outer surfaces, which act as switches that control cellular processes. Dr. Groopman’s laboratory had previously demonstrated that THC could have a protective effect against a certain form of invasive, drug-resistant lung cancer.

To study the combined effect of THC and KSHV, the researchers examined a culture of human skin cells, which are susceptible to infection and could provide a model of Kaposi’s sarcoma. These culture cells display many copies of two prominent cannabinoid receptors. Dr. Groopman and his colleagues found that by bonding to these receptors, low doses of THC activate two proteins responsible for maintaining a cell’s internal framework, or cytoskeleton. By altering the cytoskeleton, THC effectively opens the door for KSHV, allowing the virus to more easily enter and infect the cell. “We can take away that effect by using antagonists that block the two cannabinoid receptors, which adds evidence that THC is the culprit,” Dr. Groopman said.

Once a cell is infected, the presence of THC may also promote the cellular events that turn it cancerous, the researchers say. They found that THC also promotes the production of a viral receptor similar to one that attracts a cell-signaling protein called interleukin-8. Previous studies have noted that this receptor could trigger the cell to reproduce, causing Kaposi’s sarcoma-like lesions in mice. Indeed, the researchers saw that THC induced the infected cells to reproduce and form colonies in culture.

“Here we see both infection and malignancy going on in the presence of THC, offering some serious concerns about the safety of THC among those at risk,” Dr. Groopman said. “Of course, we still do not know the exact molecular events that are occurring here, but these results are just the first part of our ongoing research.”

Comments

Anti-Marijuana/ Marijuana bashing articles such as this are a complete load of crap. Increasing the chance of contracting the herpes virus only comes from increasing the number of your intimate partners. Herpes doesn't just magically appear out of thin air, and THC can't "open the door to KSHV" when a non-infected couple is in a monogamous relationship.

Just stick to the cancer research Dr. Jerome Groopman and lay off the propaganda. All people should be aware of a "scientific" article that is filled with the words "could" and "may".

I would like to see the evidence of this research, especially since there have been so many practical trials by private people that show a significant benefit from marijuana use by herpes sufferers. I would like to see an in depth study done by a variety of reputable organisiations instead of one that may clearly be biased in their views on the marijuana herb.

The title of this is very misleading. Kaposi's sarcoma herpes virus is the eighth herpes virus strain that only infects about 2% of America and Europe's population. It appears that in general the herpes viruses may have interactions with THC, but for herpes simplex-1 and 2, the suspicion is that they are actually suppressed by THC. It is not uncommon that in a single category of molecular structure, its variants may have drastically different effects in the same situation.

Also, you aren't a very good scientist if you don't see the importance and validity of using the word may. Obviously nothing is conclusive in this line of research so far, so it would be a lie to use any more definite terms. Even when scientific theories are basically proven, they are still called theories and are still considered tentative simply in the respect that the foundation of rational thinking requires that doctrine must always be flexible when new information is gathered. The title of this article is far more treacherous. It should say 'Rare herpes virus' in order to convey the correct idea. It seems like fear mongering to me, considering how many people are infected with the more common herpes strains.

Also, this article says the opposite of this study, but I can't access the original study because I don't have a subscription to BioMed. I can read it at my college library, but in the meantime maybe you can scout ahead for the original research.http://health.dailynewscentral.com/content/view/000190/47/

The great thing about science is that as time goes on, we may learn things. A cannabis advocacy publication is publishing science that it agrees with (in this case from 6 years ago) whereas we publish studies that even contradict each other because we have no agenda other than information.

Pot and pregnancy definitely should not mix, but the drug poses the greatest threat to a fetus when the mother-to-be smokes it -- or inhales it as secondhand smoke. For that reason, be sure your boyfriend never smokes around you.

"THC, the active component in marijuana, can be passed from mother to infant through breast feeding," according to the Alcohol and Drug Information Clearinghouse (prevlink.org). "This chemical is more concentrated in the mother's breast milk than it is in her blood, and use of marijuana by breast-feeding mothers has been linked to motor development problems in newborns."

Fortunately, a male's use of marijuana is not linked specifically to birth defects, though there is some evidence it can increase the likelihood of miscarriage. Your boyfriend needs to start making smarter decisions about his life, now that he faces the awesome responsibility of fatherhood.

This is hardly a "stupid" question, by the way. I'm glad you had the courage to ask it. A well-informed mother-to-be will almost certainly become an excellent mother.

Dr. Wallace -- How can a person be totally cured if he has a sexually transmitted disease? -- Nameless, San Francisco

Nameless -- No sexually transmitted disease will "go away in time" without medical treatment. Treatment often involves taking specific antibiotics to destroy the organisms causing the disease. With the exception of herpes, genital warts and HIV, most STDs can readily be cured.

Herpes can be treated to reduce the frequency and duration of outbreaks, but as yet it cannot be cured. Genital warts can be removed, but often the virus that causes them remains present on the skin. Presently, there is no cure for HIV.